William J. Mann is an American novelist, biographer, and Hollywood historian best known for his studies of Hollywood and the American film industry, especially his 2006 biography of Katharine Hepburn, Kate: The Woman Who Was Hepburn. Kate was named one of the 100 Notable Books of 2006 by the New York Times. Mann was born in Connecticut and received his Master's degree at Wesleyan University. His first novel, The Men From the Boys, was published by Dutton in 1997. His other biographies include How to Be a Movie Star: Elizabeth Taylor in Hollywood, and 2014's New York Times bestseller: Hello Gorgeous: Becoming Barbra Streisand.